Method of constructing sliders



June 10,1941. 1., H. MORIN METHOD OF CONSTRUCTING SLIDERS Original Filed July 16. 1938 INVENTOR Z d/JHMflR/N ATTORNEY Patented June 10, 1941 METHOD OF CONSTRUGTING SLIDERS Louis H. Morin, Bronx, N. Y., assignor to Whitehall Patents Corporation, Bronx, N. Y., a. corporation of New York Original application July 16, 1938, Serial No.

219,536. Divided and this application Decemher 13, 1938, Serial No. 245,417

(Cl. 1s-55 2 Claims.

This invention relates to separable fasteners and other members or elements, and particularly, as an example, to the production of sliders for separable fasteners and further to a novel method illustrated as applicable to thermoplastic sliders composed of such materials as cellulose acetate which may be readily die cast and then reformed in accordance with the method herein disclosed of constructing devices of this kind having means 5 to produce what I term an undercut in establishengaging end stops for retaining the slider against ing a looking or latching engagement of the slider movement longitudinally of the stringers when a with the pins l3, l3a. The slider consists of top pull is applied to the stringer ends tending to sepaand bottom walls l5, I6 joined by a connecting Web rate the same. More particularly the invention H at the wide end l8 of the slider, forming at said relates to the method of constructing devices, 10 end diverging channels l9 which converge into a members or elements of the type and kind here single channel at the narrow end 20 of the slider. under consideration which are constructed from The side edges of the top and bottom walls inthermoplastic material as more fully hereinafter elude inturned flanges 2| as in the general condescribed and claimed. The invention will be best struction of devices of this kind. It is also preunderstood from the following description and ferred that the top wall 15 be provided on the annexed drawing in which certain embodiments outer surface thereof with some means, such for of the invention are disclosed, the separate parts example a strap 22 for supporting the usual finger being designated by suitable reference characters piece or pull, not shown, in connection therewith. in each of the views, and in which: For purposes of simplification, the slider in the Fig. 1 is a bottom plan and sectional view of one following drawing is shown as a plain type or form of slider made according to the invention in- What might be termed non-locking type of slider; dicating its arrangement upon a portion of fasthat is to say a d r Which is not provided With tener stringers. means retaining the same against movement in Fig. 2 is a sectional view through dies or formdifierent positions longitudinally of the stringers. ing parts employed in producing an undercut or 25 It will be understood, however, that the invention ofiset recess in a groove formed in one. wall of is applicable to sliders of any type and kind. The the slider. present invention deals primarily with the pro- Fig, 3 is a plan and sectional view substantially vision of means for retaining the slider against on the line 3 3 of Fig. 2. accidental displacement when at the limit, or Fig. 4 is a view similar to Fig. 2 showing parts substantial limit, of its fully closed position, so in a. different position. that if the stringer tapes are subjected to stress Fig. 5 is a plan and sectional view showing a or strain in the direction of the arrows .L', Fig. 1, slider as produced prior to the forming operations tending to open the stringers, the slider It will herein specifically described, and be retained automatically against opening move- Figs. 6, 7 and 8 are sectional views of parts of ment, thus providing what might be termed an sliders showing modified forms of grooves which automatic look. In accomplishing this result it may be employed. 1 is also desirable to provide a means of retaining The invention forming the subject matter of the slider in this position which will, nevertheless, this application constitutes a division of my prior permit the automatic opening movement of the application Ser. No. 219,536, filed July 16, 1938, 40 slider through the medium of the usual pull, as and also relates to the production of devices of will be apparent. the general type and kind disclosed in applica- In producing a slider of the type and kind illustion Ser. No. 155,864 filed July 27, 1937. trated in Figs. 1 to 5 inclusive, the slider is first In Fig. 1 of the drawing one end portion of two formed in any desired manner, the slider in the stringers l9, 16a is shown with the interengaging structure being formed by die casting. This slider coupling links or scoops H, Hoarranged on adas formed will be provided on the inner surface jacent beaded edges thereof, and the ends of the of preferably the bottom wall It, or in fact could ers beyond e end links are provided with be applied at the inner surface of both walls in acend steps 52, 12a, each provided with downwardly, cordance with the teachings in the earlier apor downwardly and upwardly directed pins I3, l3a for latching engagement with a slider M, as later described.

While the present invention isunderstood to be applicable to fasteners, or the sliders of fasteners, of any type, kind and construction, it is herein plication herein identified, with grooves 23 opening through the large or wide end it of the slider and exposed-to each channel I9 therein. These grooves extend longitudinally of the slider in a plane substantially parallel to the longitudinal center of the slider. The grooves preferably have a flared opening, as indicated at 25, so as to permit free insertion of the pins l3, [3a.

After producing a slider in the manner illustrated in Fig, 5, the next step in the process of forming the desired contour of the grooves to adapt them for the desired function, is to form what I term an undercut or offset in at least one side wall of the grooves, preferably adjacent the inner end thereof, for example, the offset 25 in dicated in Figs. 1 and 3 of the drawing. These offsets extend outwardly and are substantially V- shaped or triangular in form to provide an angular wall 250. which is disposed in' aposition substantially transversely of the path of movement of the stringers with respect to the channels l9 or at approximately 45 to thelongitudinal center line of the slider, so that the pins [3, l3a when moved into the inner ends of the grooves, engage the angular surfaces 250. of the undercuts, thus retaining the slider against opening movement if a stress or strain is applied'to the stringers in the direction of the arrow :1: as previously stated.

In forming the undercut 25 in the workpiece, as shown in Fig. of the drawing, said workpiece is first placed upon an anvil 26 which is shaped to fit within the channels IQ of the slider in the manner illustrated in Fig. 3 of the drawing.

The anvil has raised lugs or forming elements 2''! .of the contour of the resulting undercut grooves to be formed; that is to say are provided vwith ofiset parts 2111 which form the undercuts 25. The anvil 2B is supported on a suitable block or bed-plate 28 and the forked ends of the anvil,

which are arranged within the slider hi, are so formed as to engage the inner surface of the outer wall l5, as indicated in Fig. 2 of the drawing in order to support the workpiece in proper alinement upon the anvil. After this, a punch or die'29 havinga recess 30 in the undersurface thereof corresponding tothe peripheral contour of the wall I6, is moved into engagement with theslider or the outer surface of the wall 16 to force said wall downwardly in the direction of the anvil. In this operation the projections 27a on the lugs 2'! will force the adjacent material of the wall l6 outwardly, which material will enter grooves 3| formed in the surface of the punch or the recess'3fl therein. The result of this operation is illustrated in Fig. 4 of the drawing; It will be understood that the punch or die 29 is then raised and the workpiece removed from the anvil by first moving the same upwardly to disengage the lugs from the resulting undercut grooves formed in the workpiece, which are of Y the contour illustrated in Fig. 1 of the drawing.

When removed, the slider or resulting workpiece may now be trimmed and otherwise finished to remove the protruding portions I611. disposed on the outer surface of the wall It of the slider, especially if a neat and finished slider is desired. In some instances, however, these projecting portions need not be removed, as they will in no way interfere with the successful operation of the slider. The above operation of forming the undercuts or offset portions in the grooves of therslider when constructing the latter from thermoplastic materials, will be performed when the material is in a warm or heated condition, that is to say heated su fficiently to render the material thereof workable,

warm, or if desired, these devices may be reheated for performing this and any other operation desired thereon in the production of the finished slider. At this time it is well to call attention to the fact that any type or kind of undercut may be formed in a workpiece in accordance with the method herein disclosed, regardless of the structure of the workpiece or the intended use thereof. This is especially true in dealing with various kinds and classes of thermoplastic devices.

In Fig. 6 of the drawing another form of undercut is illustrated, and while only one-half 'of the slider is shown, it will be understood that both sides of the slider may be of the same construction. In this figure, the normal grooves formed in the slider are illustrated at 23a, and the undercut instead of being abrupt and located definitely at the inner end of the grooves, extends longitudinally of one wall of the grooves in a slider, tapered, as is indicated at 32. This type of undercut will have an effective locking or latching surface of greater length longitudinally of the slider than with the structure shown in Figs. 1 and 3. On the other hand, the reduced angularity of the engaged wall will provide a freer detachment of the slider in the positive manual movement thereof longitudinally of the stringers from theclosed to open positions.

- In Fig. '7 of the drawing I have shown a slider which is provided with a double undercut, that is to say in addition to the undercut 32, the opposed wall of the initial grooves 23b is provided with an inner undercut 33. The latter provides a greater freedom of action of the pins l3, I30; and will produce what might be termed a full dove-tailed groove, whereas the structures in Figs. 1 to 6 inclusive, might be said to be semi-dove-tailed grooves.

In Fig. 8 another form of construction is shown wherein the normal grooves 230 have an undercut 34 at the inner ends thereof which is semicircular in form. The circular formation of the undercut 34 is sufficiently large to freely receive the pins l3, I3a, but are not of such contour as to form. a definite lock which would prevent manual movement of the slider into open position, but would effectively produce a latching or locking wall 3411.

This construction is substantially the same as a the undercut disclosed in the application herein identified, but is formed without the necessity of drilling the holes through the wall of the slider as is taught in said earlier application. Furthermore with a structure of the type and kind herein disclosed, made in accordance with the method herein defined, it will be apparent that by the proper formation of the die lugs on the anvil, and desired degree of angularity and/or contour can be formed on the undercut, while at the same time the contour of the grooves as a whole, or at least the boundary walls thereof, may be changed. In fact it would also be possible, within the limits of movement of the anvil transversely with respect to the walls of the slider, to form other irregular contours in the bottom wall of the grooves, if desired.

At this time it is well to call attention to the fact that while it is preferred to preform a part of the desired grooves in the workpiece in accordance with the casting operations thereof in the manner which is permitted without complicating the dies employed in forming such die castlngs, it is also possible to form the workpiece with a plain or ungrooved surface and to form the entire grooves therein by means of the die member or element on the anvil which forms on part of what may be termed two die members. Another objection to the latter procedure is in extending a large amount of material of the casting to the outer surface of the wall, in which the groove or grooves are formed, and the added work which would be required in removing these protruding bodies if removal is desired.

To more broadly express the invention herein disclosed, apart from the present disclosure which is illustrative of one method or mode of carrying the invention into effect, it may be said that the invention consists in first preforming a body or element by die casting the same, especially as applied to a die cast thermoplastic body or element, and then subjecting such body or element to what may be termed a die forming operation wherein a part of the material of said body or element is displaced from one wall or surface and extended through another or opposed Wall, and especially in forming grooves, recesses or impresses in the body or element which are not capable of being formed in a simple economical manner by the initial casting dies or parts thereof, thereby facilitating the production in die cast bodies, of structural contours which heretofore have been deemed impossible or which heretofore have necessitated the performance of drilling or other machine operations rather than die forming operations.

In forming grooves on the inner surfaces of both the top and bottom walls in the manner heretofore indicated and as specifically disclosed in the application herein cited, it will be understood that the workpiece is simply reversed upon the anvil and the operation performed in accordance with the teachings illustrated in Figs. 2 and 4 of the drawing, it being understood that the recess 30 of the die or tool 29 will be characterized or shaped to receive the strap element 22 on the outer surface of the wall IE or any other element or part which may be arranged thereon, so long as the latter does not interfere with or register with the grooves 3| employed for receiving the displaced material.

Having fully described my invention, what I claim as new and desire to secure by Letters Patent is:

1. The herein described method of forming undercut recesses on the inner surface of one of two spaced and opposed thin walls of a hollow body, which comprises placing one forming tool having a projecting part shaped to form the desired undercut in said hollow body between said walls, said tool with the projection having less thickness than the space between said opposed walls, arranging another tool outwardly of the wall to be formed and in alinement with the first named tool, then moving said tools together to outwardly displace material from the inner surface of a predetermined section of said wall to form an undercut recess in said surface, then separating the tools from said wall by moving at least one tool away from the surface of the wall engaged thereby, and then removing the first named tool from said body.

2. The herein described method of forming undercuts at the inner ends of grooves formed on the inner surface of at least one wall of a slider having opposed spaced walls with a chamber therebetween, which comprises arranging in the chamber of the slider one forming tool having projecting parts shaped to form the desired undercuts in the grooves of said slider wall, said tool with the projections having less thickness than the space between said opposed walls, arranging another tool outwardly of the wall to be formed and in alinement with the first named tool, then moving at least one of said tools in the direction of the other to outwardly displace material from the inner surface of the grooved wall of the slider to form the undercuts in said surface, then separating the tools, and removing the first named tool from the chamber of said slider.

LOUIS H. MORIN. 

